Evaluation of nine pesticide residues in three minor tropical fruits from southern China

The residue levels of nine pesticides (imidacloprid, acetamiprid, carbendazim, diflubenzuron, chlorbenzuron, phoxim, pyrimethanil, abamectin and iprodione) in 117 samples of three minor tropical fruits (starfruits, wax apples and Indian jujubes) from Hainan, Fujian, Guangdong and Guangxi provinces in China were analyzed using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) after multi-residue extraction procedures. A total of 78 (66.7%) samples were positive, with residues above the limit of quantification. Indian jujube was the fruit with the highest percentage of positive samples (81.6%), followed by starfruit (61.0%) and finally wax apple (57.9%). Carbendazim was the most frequently detected residue found in 51 (43.6%) samples in the concentration ranges of 34.0–443.8 μg/kg. Diflubenzuron, phoxim, pyrimethanil and abamectin were not detected in any sample. Twenty-nine (24.8%) samples were contaminated with multiple pesticide residues, and the simultaneous occurrence of three different residues was found in one wax apple and two starfruit samples. Estimation of the potential health risks associated with the exposure to the analyzed pesticides was carried out and the estimated daily intakes (EDIs) were very low, ranging from 0.020% of the acceptable daily intakes (ADIs) for chlorbenzuron to 1.13% for carbendazim. These results indicate that despite a high occurrence of pesticides in starfruit, wax apple and Indian jujube, the contamination levels do not contribute significantly to pesticide intakes and are unlikely to have public health effects. Nevertheless, measures should be taken to hasten the registration of pesticides for use on minor fruit crops. The findings also indicate that routine monitoring of pesticide residues in minor fruits is necessary to prevent, control and reduce pesticide contamination and to minimize health risks.     

基于免疫磁分离的7种产志贺毒素大肠埃希氏菌快速检测方法的评价

目的 研究基于免疫磁分离的七种产志贺毒素大肠埃希氏菌快速检测方法的灵敏度与特异性。方法 将大肠埃希氏菌O157：H7和大肠埃希氏菌O103不同稀释度的菌悬液,用免疫磁珠富集后,检测其携带毒力基因stx1、stx2 和黏附基因eae以及O157:H7和O103的抗原基因。同时,对菌悬液进行活菌计数,进行灵敏度研究。对8株携带stx1、stx2、eae基因的目标菌菌悬液,以及25株非目标菌的标准菌株及分离菌株的菌悬液,用免疫磁珠富集后,检测其携带毒力基因stx1、stx2 和黏附基因eae以及抗原基因,进行特异性研究。结果 本方法检测大肠埃希氏菌O157：H7的stx1、stx2、eae以及抗原基因的灵敏度为10_²CFU/mL,检测大肠埃希氏菌O103抗原基因的灵敏度为10_³CFU/mL. 8株目标菌检测结果与其携带的基因一致,没有假阴性,包容性达到100%。25株目标菌检测结果与其携带的基因一致,未发现有假阳性,排他性达到100%。结论 方法具有良好的灵敏性及特异性,适用于食品中七种产志贺毒素大肠埃希氏菌的快速检测。